The present invention relates to a system of modular elements for machining marble, stone and the like. The machining of marble, stone and the like which requires the removal of a large quantity of material presents numerous difficulties even when using diamond tools.
The removal of large amounts of material either for excavating cavities or for at least the rough finishing of deep shapings on slabs is done by chiselling, drilling and fragmenting the excess material, or by successive passes of diamond tools.
All these known techniques have many drawbacks: in the case of chiselling or core drilling and fragmenting the excess material, the operations require a considerable amount of time and labour. When using diamond tools the operations are slow and costly owing to the wear of the said diamond tools.
Moreover, in the case of deep shapings, when profiled diamond tools are used that part of the tool which removes a large quantity of material will obviously suffer greater wear than that part or parts which remove less material. The life of the profiled diamond tool is therefore limited to the life of the diamond part performing most of the removal work, while the part which has done xe2x80x9clittlexe2x80x9d work or no work at all suffers limited or zero wear. When one part of the diamond material of such a tool is worn the entire profiled tool must be replaced, with a consequent waste of non-worn diamond since these tools cannot be reconstructed or made new again as can be done, for example, with a bonded grinding wheel, which can be revived or re-profiled owing to the fact that the diamond part is a thin layer of diamonds only on the surface of the profiled tool. Once some of the coating is worn, the tool must be scrapped even if part of the diamond coating is still useable. This obviously increases costs.
Clearly, with profiled diamond tools the marble or stone or the like is all removed by abrasion: the amount of diamond necessary per unit of surface area of the tool is therefore large.
Furthermore, each type of shaping or profile necessitates a xe2x80x9cnegativexe2x80x9d shaped tool with corresponding diamond coating for each design of shaping or profile, making it necessary to immobilize capital in keeping a large assortment of tools.
The chief object of the present invention is to provide a system of the abovementioned type that combines the advantages of diamond machining and fragmentation machining, bringing together the advantages of the individual techniques.
Another object of the present invention is to provide a system of the abovementioned type in which a plurality of elementary tools can be assembled together to form any desired profile and that will be particularly efficient at quickly and inexpensively performing profiling work of the abovementioned kind while reducing the inventory of tools and so cutting costs and increasing machining speeds.
The present invention provides a system of modular elements for the abovementioned objects comprising a plurality of disc elements with diamond outer rings for assembling on a single supporting drive spindle with a spacing approximately equal to their depth; mechanical fragmenting means being provided in the spaces between the disc elements to operate essentially by impact, in contrast to the abrasive action of the diamond outer ring of the said disc elements; which disc elements have different diameters forming a broken line that corresponds substantially to the outline of the profile or shaping to be produced on marble, stone or the like; the arrangement being such that the disc elements cut grooves by diamond abrasion and the mechanical fragmenting means shatter the parts projecting from the grooves with an action of fragmentation by impact or by brittle fracture.